de Haan, 1833
Small symbiotic crabs, usually living as commensals, exhibiting degeneration of some organs and a strong sexual dimorphism. Carapace usually more or less round or transversely elliptical. Antero-lateral margins smooth or with minute teeth. Front narrow, orbits and eyestalks very small. Cornea sometimes indistinct. Antennules and antennae usually very small and cramped. Interantennular septum, when distinguishable, as a thin plate. Buccal cavern very broad, short, usually semicircular. Third maxillipeds variable; merus often very large; ischium often very small, sometimes vanished or fused with merus; exopodite very reduced. Female openings sternal. Male openings in sternal position, derived from a coxal location. Male abdomen narrow. (Guinot 1998)
Subfamilies treated:
subfamily Asthenognathinae Stimpson, 1858
subfamily Pinnothereliinae Alcock, 1900
subfamily Pinnotherinae de Haan, 1833
subfamily Xenophthalminae Alcock, 1900